(a) Field of the Invention
Embodiments of the invention relate to a solar cell.
(b) Description of the Related Art
Recently, as exhaustion of existing natural resources such as petroleum and coal is anticipated, interest in alternative energy is increasing, and in this respect, solar cells producing electric power from solar energy are receiving attention.
A solar cell generally includes semiconductor parts that have different conductivity types, such as a p-type and an n-type, and form a p-n junction, and electrodes respectively connected to the semiconductor parts of the different conductivity types.
When light is incident on the solar cell, electron-hole pairs are generated in the semiconductor parts. The electrons move to the n-type semiconductor part and the holes move to the p-type semiconductor part, and then the electrons and holes are collected by the electrodes connected to the n-type semiconductor part and the p-type semiconductor part, respectively. The electrodes are connected to each other using electric wires to thereby obtain electric power.
The electrodes are positioned on the semiconductor part at an incident surface of the solar cell on which light is incident as well as on the semiconductor part at an opposite surface to the incident surface, on which light is not incident. Thus, an incident area of light is reduced by the electrodes positioned on the incident surface to decrease an efficiency of the solar cell.
For increasing the incident area, a back contact solar cell, of which all electrodes are positioned on the opposite surface to the incident surface has been developed.